Gordius digitatus, Schmidt-Rhaesa, Andreas, 2010

Schmidt-Rhaesa, Andreas, 2010, Considerations on the genus Gordius (Nematomorpha, horsehair worms), with the description of seven new species, Zootaxa 2533, pp. 1-35 : 22

Gordius digitatus sp. nov.

( Fig. 7 D–E)

Type material: 13, Holotype: Zoological Museum Hamburg, ZMH V13271 .

Type locality. Croatia, Plitvice Lakes (Plitvička Jezera) (coll. August 8, 2000 by M. Teiwes).

Other material examined. No further material.

Etymology. The name refers to the shape of the areoles which interdigitate with each other.

Description. The body color is very light brown; white spots are absent. The anterior end includes a white tip followed by a very weakly darker colored collar. The specimen is 110 mm long and has a diameter of 0.4 mm.

The postcloacal crescent is short and moderately bent ( Fig 7 E). It is directly at the point of bifurcation, but the arms extend only slightly onto the tail lobes. The tail lobes are a bit shorter than their double diameter, the inner side is only very slightly concave. Scattered tiny bristles are present on the entire posterior end, lacking only in the immediate neighbourhood of the cloacal opening ( Fig. 7 E). The shape of the cloacal opening itself could not be observed because it is covered by dirt or sperm.

The cuticle includes areoles of variable shape ( Fig. 7 D). Sometimes, areoles are rounded or polygonal and may fuse with neighbouring areoles ( Fig. 2 D), but the cuticle also contains areoles of irregular shape, forming digits that interdigitate with neighbouring areoles like a jigsaw ( Fig. 7 D). The cuticle is covered with smooth patches considered to be contaminations ( Fig. 2 D).

Remarks. All areoles that have been reported from Gordius species are roundish or polygonal in shape. The presence of interdigitating irregularly shaped areoles is therefore a new pattern characteristic for this species.

Figures

FIGURE 2. Cuticular characters under lower magnifications in Gordius. A. Polygonal areoles on the cuticle of Gordius cf. tatrensis (collection Schmidt-Rhaesa # 623.2). B. Smooth cuticle in G. aquaticus (SR 901). C. Bristles on smooth cuticle in an undetermined Gordius specimen from Montenegro (SR 969). D. Contamination plaques of unknown nature on the cuticle of G. digitatus (ZMH V 13271). E. Star-like crystals on the cuticle of G. aquaticus (SR 839). F. Blossomlike crystals on the cuticle of G. aquaticus from Germany (SR 839). G. Uneven cuticular surface of a G. aquaticus specimen (SR 839). H. Smooth cuticle in an undetermined Gordius specimen from Estonia (SR 1006).

FIGURE 7. Gordius balcanicus and G. digitatus. A – C. Gordius balcanicus sp. nov., D – E. G. digitatus sp. nov. A, E. Posterior ends. B. Cuticle under low magnification. C. Cuticle showing broad ridges separated by grooves. D. Cuticle showing irregular shape of areoles.